Grain that has been processed by a threshing machine, such as a combine, frequently contains undesired foreign particles such as weed seeds, chaff, broken kernels and other foreign particles which it is very desirable to remove prior to storing the grain for use or sale. Such extraneous fine materials interfere with air flow when the grain is being dried and stored and can cause areas of spoiled grain.
Screeners for cleaning grain and the like have included one or more rotary screens to separate the grain from foreign materials. In one type of screener, the outer drum includes a cylindrical screen supported by a plurality of axially spaced rims. The grain to be cleaned is supplied into the drum which has a fine mesh screen to allow fine foreign materials to pass the screen. The grain collected in the fine mesh screen is removed from one end of the drum.
In one type of construction, an auger conveyor extends longitudinally within a rotary, cylindrical screen and an elongate baffle member is disposed in the space between the auger conveyor and the screen and encloses only a portion of the auger conveyor. In addition, an auger conveyor element is mounted on the outside of the separating screen and rotatable therewith. Drive means are provided for rotating the drum and the auger conveyor.